Cargo and registered luggage in large-capacity aircraft is transported by means of air cargo containers and pallets, so-called unit load devices (hereinafter referred to as ULD). Manual loading is often made inefficient by the high loading capacity and objective of short idle times for large-capacity aircraft.
During the loading process, ULD's are generally fixed in their final position at the edge rails of their floor plate by way of latches inside the cargo holds of aircraft. Positioning here takes place by way of roller mats (ball mats, ball strips, ball transfer units) or roller tracks inside the cargo hold of the aircraft.
In addition to manual positioning, so-called power drive units (PDU) can be used for electrical positioning. These consist of an electrical drive, a gearbox, as well as a powered, rubber-coated roller, which is mounted in a roller track.
During the loading process, the edge rails of the ULD are moved up to the latches inside the cargo hold. The latter here form a stop for the edge rails. Once the final position of the ULD has been reached, the latches are clamped on the upper side of the edge rails of the ULD. As a result, the ULD is fixed in place, and now only allows a slight shifting.
The edge rails of a ULD generally consist of stiff metal profiles, which rigidly encase the floor plate of the cargo container on all sides. Rivet joints or other conventional bonding techniques are generally used to bond the floor plate with the edge rails.
In the aforementioned systems, critical dynamic loads (forces and moments) can be reached during loading processes and flight operations, which can lead to significant damage to the latches and entire floor structure inside the cargo holds of aircraft. For example, the high dynamic loads can stem from the stiff and coupled structure of a floor plate, a container jacket and edge rails of a ULD.
DE 10 2004 039 666 A1 and US 2007/0253790 A1 show a device for latching objects, in particular in an aircraft.
DE 10 2005 061 957 A1 shows a latching device for securing useful payload containers, in which a gap can be introduced between the payload container and latching device by means of a locking element.